High-temperature regenerator

ABSTRACT

In a high-temperature regenerator which has vertical liquid pipe groups in the proximity of which a combustion flame and combustion gas from a burner pass and a double can wall which communicates with upper and lower portions of liquid pipes forming the vertical liquid pipe groups and is arranged at a position of a furnace wall and which heats and concentrates a diluted absorption solution passing through the vertical liquid pipe groups and the double can wall, a solution inlet for sprinkling the diluted absorption solution in an open state is provided above liquid pipes arranged on a side opposite to the burner. Since the sprinkled diluted absorption solution collects the heat of an exhaust gas while it falls to increase its temperature, when it flows into the other liquid pipes, it boils immediately and its circulation flow is activated by boiling. Therefore, total heat transfer coefficient can be increased, a local rise in the temperature of the liquid pipe groups and the can wall can be avoided, and such inconvenience as a corrosion accident and the crystallization of a solution caused by this rise in temperature can be prevented.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to the structure of a high-temperatureregenerator for use in an absorption refrigerator.

2. Background Art

A high-temperature regenerator provided in an absorption refrigerator(including what is called absorption water cooler or heater) takes upthe greater part of the entire absorption refrigerator in terms ofweight and volume. Therefore, to make compact the absorptionrefrigerator, it is essential to reduce the size and weight of thishigh-temperature regenerator. It is also necessary to reduce thedischarge of NOx at the time of combustion as an environmental problemin the high-temperature regenerator.

Conventional high-temperature regenerators generally employ a flue andsmoke tube system or a flue and liquid tube system. Since it isimpossible for the high-temperature regenerators of these systems toeliminate a combustion chamber as a flue, it is difficult to makecompact these types of high-temperature regenerators. In other words,the discharge of NOx cannot be reduced when the high-temperatureregenerator is made compact, and reductions in the size and weight ofthe high-temperature regenerator conflict with a reduction in thedischarge of NOx.

As what breaks through the limitation of the flue and smoke tube systemor the flue and liquid tube system, a flue-less liquid pipe group systemin which a plane combustion surface is formed without a combustionchamber has been introduced into a gas fired boiler in recent years. Inthis flue-less liquid pipe group system, since a combustion flame andcombustion gas from a burner such as a plane combustion surface aredirectly introduced into liquid pipe groups, a combustion chamber is notrequired, thereby making it possible to make the boiler extremelycompact and reduce the discharge of NOx.

However, in the above flue-less liquid pipe group system, a combustionflame and combustion gas from the burner pass in the proximity of theliquid pipe groups. Therefore, the exterior surfaces of the liquid pipesare covered with high-temperature flames and further the heat transfercoefficient of an absorption solution in the pipes is greatly reduced ascompared with water, whereby the temperature of the interior wallsurface of each pipe is locally increased. As a result, suchinconvenience as a corrosion accident or the crystallization of asolution may occur by the local overheating and concentration of anabsorption solution caused by a local rise in temperature.

SUMMARY OF THE INVENTION

It is therefore an object of the present invention which has been madeto solve the above problems to provide a high-temperature regenerator ofa flue-less liquid pipe group system having no combustion chamber butliquid pipe groups in the proximity of which a combustion flame andcombustion gas pass, which can prevent inconvenience caused by a localrise in temperature.

To attain the above object, according to a first aspect of the presentinvention, there is provided a high-temperature regenerator which hasvertical liquid pipe groups in the proximity of which a combustion flameand combustion gas from a burner pass and a double can wall whichcommunicates with upper and lower portions of liquid pipes forming thevertical liquid pipe groups and is arranged at a position of a furnacewall and which heats and concentrates a diluted absorption solutionpassing through the vertical liquid pipe groups and the double can wall,wherein a solution inlet for sprinkling the diluted absorption solutionin an open state is provided above liquid pipes arranged on a sideopposite to the burner.

According to a second aspect of the present invention, there is provideda high-temperature regenerator which has vertical liquid pipe groups inthe proximity of which a combustion flame and combustion gas from aburner pass and a double can wall which communicates with upper andlower portions of liquid pipes forming the vertical liquid pipe groupsand is arranged at a position of a furnace wall and which heats andconcentrates a diluted absorption solution passing through the verticalliquid pipe groups and the double can wall, wherein solution inlets forsprinkling the diluted absorption solution in an open state are providedin upper portions of both right and left sides or an upper portion ofeither one of the sides of a portion on a side opposite to the burner ofthe double can wall.

According to a third aspect of the present invention, there is provideda high-temperature regenerator which has vertical liquid pipe groups inthe proximity of which a combustion flame and combustion gas from aburner pass and a double can wall which communicates with upper andlower portions of liquid pipes forming the vertical liquid pipe groupsand is arranged at a position of a furnace wall and which heats andconcentrates a diluted absorption solution passing through the verticalliquid pipe groups and the double can wall, wherein solution inlets forsprinkling the diluted absorption solution in an open state aredistributed in a longitudinal direction of upper portions of both rightand left sides or an upper portion of either one of the sides of thedouble can wall.

According to a fourth aspect of the present invention, there is provideda high-temperature regenerator which has vertical liquid pipe groups inthe proximity of which a combustion flame and combustion gas from aburner pass and a double can wall which communicates with upper andlower portions of liquid pipes forming the vertical liquid pipe groupsand is arranged at a position of a furnace wall and which heats andconcentrates a diluted absorption solution passing through the verticalliquid pipe groups and the double can wall, wherein solution inlets forcausing the diluted absorption solution to flow in by means of pumppressure are provided below liquid pipes arranged on the side of theburner.

According to a fifth aspect of the present invention, there is provideda high-temperature regenerator which has vertical liquid pipe groups inthe proximity of which a combustion flame and combustion gas from aburner pass and a double can wall which communicates with upper andlower portions of liquid pipes forming the vertical liquid pipe groupsand is arranged at a position of a furnace wall and which heats andconcentrates a diluted absorption solution passing through the verticalliquid pipe groups and the double can wall, wherein first solutioninlets for causing the diluted absorption solution to flow in by meansof pump pressure are provided below liquid pipes arranged on the side ofthe burner, and a second solution inlet for sprinkling the dilutedabsorption solution in an open state is provided above liquid pipesarranged on a side opposite to the burner, or in upper portions of bothright and left sides or an upper portion of either one of the sides of aportion on a side opposite to the burner of the double can wall, ordistributed in a longitudinal direction of upper portions of both rightand left sides or an upper portion of either one of the sides of thedouble can wall.

According to a sixth aspect of the present invention, there is provideda high-temperature regenerator which has vertical liquid pipe groups inthe proximity of which a combustion flame and combustion gas from aburner pass and a double can wall which communicates with upper andlower portions of liquid pipes forming the vertical liquid pipe groupsand is arranged at a position of a furnace wall and which heats andconcentrates a diluted absorption solution passing through the verticalliquid pipe groups and the double can wall, wherein the high-temperatureregenerator comprises:

dividing means for dividing the liquid pipes into liquid pipes arrangedon the side of the burner and liquid pipes arranged at a downstream sidethereof so that they do not communicate with each other;

solution inlets for causing the diluted absorption solution to flow intolower portions of liquid pipes on the side of the burner by means ofpump pressure; and

sprinkling means for sprinkling the diluted absorption solution flowingout from upper portions of the liquid pipes on the side of the burnerover upper portions of the liquid pipes at a downstream side in an openstate.

According to a seventh aspect of the present invention, there isprovided a high-temperature regenerator which has vertical liquid pipegroups in the proximity of which a combustion flame and combustion gasfrom a burner pass and a double can wall which communicates with upperand lower portions of liquid pipes forming the vertical liquid pipegroups and is arranged at a position of a furnace wall and which heatsand concentrates a diluted absorption solution passing through thevertical liquid pipe groups and the double can wall, wherein thehigh-temperature regenerator comprises:

dividing means for dividing the liquid pipes into liquid pipes arrangedon the side of the burner and liquid pipes arranged at a downstream sidethereof so that they do not communicate with each other;

first solution inlets for causing the diluted absorption solution toflow into lower portions of the liquid pipes on the side of the burnerby means of pump pressure;

a second solution inlet for sprinkling the diluted absorption solutionover upper portions of the liquid pipes at a downstream side; and

sprinkling means for sprinkling the diluted absorption solution flowingout from upper portions of the liquid pipes on the side of the burnerover upper portions of the liquid pipes at a downstream side in an openstate.

According to an eighth aspect of the present invention, there isprovided a high-temperature regenerator which has vertical liquid pipegroups in the proximity of which a combustion flame and combustion gasfrom a burner pass and a double can wall which communicates with upperand lower portions of liquid pipes forming the vertical liquid pipegroups and is arranged at a position of a furnace wall and which heatsand concentrates a diluted absorption solution passing through thevertical liquid pipe groups and the double can wall, thehigh-temperature regenerator comprises:

dividing means for dividing the vertical liquid pipes into a first groupclose to the burner, a second group farther from the burner than thefirst group and through which a high-temperature combustion gas passes,and a third group, father from the burner than the second group andprovided on the side of the outlet of the combustion gas, for collectingthe heat of an exhaust gas so that the liquid pipes of the first andsecond groups do not communicate with each other in lower portionsthereof and the liquid pipes of the second and third groups do notcommunicate with each other in a vertical direction;

a solution inlet for supplying the diluted absorption solution into theliquid pipes of the third group; and

a bypass route for introducing the diluted absorption solution passingthrough the liquid pipes of the third group into lower portions of theliquid pipes of the first group.

According to a ninth aspect of the present invention, there is provideda high-temperature regenerator of the fourth, fifth, sixth and seventhaspects, wherein the solution inlets for causing the diluted absorptionsolution to flow in by means of pump pressure have an introductionstructure formed by openings for passing the diluted absorption solutionand guide means for regulating an inflow of the diluted absorptionsolution into side portions of the double can wall and guiding it mainlyinto lower portions of the liquid pipes.

According to a tenth aspect of the present invention, there is provideda high-temperature regenerator of the ninth aspect, wherein theintroduction structure is formed by a box having openings below liquidpipes.

According to an eleventh aspect of the present invention, there isprovided a high-temperature regenerator of the ninth aspect, wherein theopenings of the introduction structure are smaller than the liquid pipesin inner diameter.

According to a twelfth aspect of the present invention, there isprovided a high-temperature regenerator of the eleventh aspect, whereinthe openings of the introduction structure project toward the lowerportions of the liquid pipes.

These and other objects and advantages of the present invention willbecome clear by the following description of preferred embodiments ofthe present invention with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram of a whole absorption refrigeratoraccording to first, eighth and ninth aspects of the present invention;

FIGS. 2A to 2C show key parts of a high-temperature regeneratoraccording to a first aspect of the present invention provided in theabsorption refrigerator of FIG. 1, wherein FIG. 2A is a horizontalsectional view, FIG. 2B a vertical sectional front view and FIG. 2C avertical sectional side view;

FIGS. 3A to 3C show key parts of a high-temperature regeneratoraccording to a second embodiment of the present invention, wherein FIG.3A is a horizontal sectional view, FIG. 3B a vertical sectional frontview and FIG. 3C a vertical sectional side view;

FIGS. 4A to 4C show key parts of a high-temperature regeneratoraccording to a third embodiment of the present invention, wherein FIG.4A is a horizontal sectional view, FIG. 4B a vertical sectional frontview and FIG. 4C a vertical sectional side view;

FIG. 5 is a schematic diagram of a whole absorption refrigeratoraccording to fourth and sixth embodiments of the present invention;

FIG. 6A to FIG. 6D show key parts of a high-temperature regeneratoraccording to a fourth embodiment of the present invention provided inthe absorption refrigerator of FIG. 5, wherein FIG. 6A is a horizontalsectional view, FIG. 6B a vertical sectional front view, FIG. 6C avertical sectional side view, and FIG. 6D a vertical sectional frontview;

FIG. 7 is a schematic diagram of a whole absorption refrigeratoraccording to fifth and seventh embodiments of the present invention;

FIG. 8A to FIG. 8C show key parts of a high-temperature regeneratoraccording to a fifth embodiment of the present invention provided in theabsorption refrigerator of FIG. 7, wherein FIG. 8A is a horizontalsectional view, FIG. 8B a vertical sectional front view, and FIG. 8C avertical sectional side view;

FIG. 9A to FIG. 9C show key parts of a high-temperature regeneratoraccording to a sixth embodiment of the present invention, wherein FIG.9A is a horizontal sectional view, FIG. 9B a vertical sectional frontview and FIG. 9C a vertical sectional side view;

FIG. 10A to FIG. 10C show key parts of a high-temperature regeneratoraccording to a seventh embodiment of the present invention, wherein FIG.10A is a horizontal sectional view, FIG. 10B a vertical sectional frontview and FIG. 10C a vertical sectional side view;

FIG. 11 is a schematic diagram of an absorption refrigerator showinganother use example of a high-temperature regenerator according to fifthand seventh aspects of the present invention;

FIG. 12A to FIG. 12C show key parts of a high-temperature regeneratoraccording to an eighth embodiment of the present invention, wherein FIG.12A is a horizontal sectional view, FIG. 12B a vertical sectional frontview and FIG. 12C a vertical sectional side view; and

FIG. 13A to FIG. 13C show key parts of a high-temperature regeneratoraccording to a ninth embodiment of the present invention, wherein FIG.13A is a horizontal sectional view, FIG. 13B a vertical sectional frontview and FIG. 13C a vertical sectional side view.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

(First Embodiment)

A first embodiment of the present invention is described hereinunderwith reference to FIGS. 1 and 2A to FIG. 2C.

With reference to FIG. 1, the whole configuration of an absorptionrefrigerator equipped with a high-temperature regenerator according tothis embodiment is outlined.

In the figure, reference numeral 1 is the barrel (lower barrel) of anevaporator/absorber, and an evaporator 2 and an absorber 3 are housed inthis lower barrel 1. Reference numeral 4 is a high-temperatureregenerator according to this embodiment which is equipped with a gasburner 5. An absorption solution pump P, a low-temperature heatexchanger 7 and a high-temperature heat exchanger 8 are provided along adiluted absorption solution pipe 6 which extends from the absorber 3 tothe high-temperature regenerator 4.

Reference numeral 10 is an upper barrel, and a low-temperatureregenerator 11 and a condenser 12 are housed in the upper barrel 12.Numeral 13 is a refrigerant vapor pipe extending from thehigh-temperature regenerator 4 to the low-temperature regenerator 11, 16a refrigerant solution downflow pipe extending from the condenser 12 tothe evaporator 2, 17 a refrigerant circulation pipe connected to theevaporator 2, 18 a refrigerant pipe and 21 a cold water pipe connectedto the evaporator 2.

Denoted by 22 is an intermediate absorption solution pipe extending fromthe high-temperature regenerator 4 to the high-temperature heatexchanger 8, 23 an intermediate absorption solution pipe extending fromthe high-temperature heat exchanger 8 to the low-temperature regenerator11, 25 a concentrated absorption solution pipe extending from thelow-temperature regenerator 11 to the low-temperature heat exchanger 7,26 a concentrated absorption solution pipe extending from thelow-temperature heat exchanger 7 to the absorber 3, and 29 a coolingwater pipe.

During the operation of the absorption refrigerator configured asdescribed above, the gas burner 5 of the high-temperature regenerator 4burns, a diluted absorption solution such as an aqueous solution oflithium bromide (LiBr) (containing a surfactant) flowing from theabsorber 3 is heated and boiled, and refrigerant vapor is separated fromthe diluted absorption solution. Thereby, the diluted absorptionsolution is concentrated.

The refrigerant vapor flows into the low-temperature regenerator 11through the refrigerant vapor pipe 13. A refrigerant solution obtainedby heating and condensing an intermediate absorption solution from thehigh-temperature regenerator 4 in the low-temperature regenerator 11flows into the condenser 12. In the condenser 12, the refrigerant vaporflowing from the low-temperature regenerator 11 condenses and flows downinto the evaporator 2 together with the refrigerant solution flowingfrom the low-temperature regenerator 11.

In the evaporator 2, the refrigerant solution is sprinkled by theoperation of the refrigerant pump 18. Then, cold water which is cooledby this sprinkling to lower its temperature is supplied to a load. Therefrigerant vapor gasified in the evaporator 2 flows into the absorber 3and absorbed into the sprinkled absorption solution.

Meanwhile, the intermediate absorption solution whose concentration isincreased by the separation of the refrigerant vapor in thehigh-temperature regenerator 4 flows into the low-temperatureregenerator 11 through the intermediate absorption solution pipe 22, thehigh-temperature heat exchanger 8 and the intermediate absorptionsolution pipe 23.

The intermediate absorption solution is heated by a heater 14 throughwhich the refrigerant vapor from the high-temperature regenerator 4flows. The concentration of the absorption solution is further increasedby the separation of the refrigerant vapor from the intermediateabsorption solution.

The concentrated absorption solution heated and condensed in thelow-temperature regenerator 11 flows into the concentrated absorptionsolution pipe 25 and further into the absorber 3 through thelow-temperature heat exchanger 7 and the concentrated absorptionsolution pipe 26 and drops over a cooling water pipe 29 from asprinkling unit 30. The concentrated absorption solution absorbs therefrigerant vapor from the evaporator 2 to increase the concentration ofthe refrigerant contained therein. The absorption solution having anincreased concentration of the refrigerant is preheated in thelow-temperature heat exchanger 7 and the high-temperature heat exchanger8 by the drive force of an absorption solution pump P and flows into thehigh-temperature regenerator 4.

A description is subsequently given of the high-temperature regenerator4.

As shown in FIG. 1, a fuel gas 31 introduced into a gas burner 5 (to besimply referred to as "burner" hereinafter) of the high-temperatureregenerator 4 and air supplied by a blower 33 are mixed together andignited to start combustion.

As shown in FIGS. 2A to FIG. 2C, a combustion flame and combustion gasfrom the burner 5 are blown directly against a large number of verticalliquid pipe groups 37 (37A, 37B and 37C) through a burner inlet 35 andpass in the proximity of the vertical liquid pipe groups 37. Thereby, aflue (combustion chamber) which is required for the conventional flueand smoke tube system and flue and liquid tube system is not necessary,thereby making it possible to make compact the high-temperatureregenerator and reduce flame temperature and the discharge of NOx.

As for these vertical liquid pipe groups 37, a large number of liquidpipes 39 are arranged in a vertical direction and a diluted absorptionsolution flows therethrough. Upper and lower portions of each liquidpipe 39 communicate with a double can wall 41. This can wall 41 isarranged at a position of a furnace wall where a combustion flame andcombustion gas pass and has an upper surface portion 41A, a lowersurface portion 41B and side surface portions 41C, and the dilutedabsorption solution passes therethrough.

In other words, as shown in FIGS. 2A to 2C, the diluted absorptionsolution passes through a space 62 surrounded by an outer shell 60 andan inner shell 61 and the large number of liquid pipes 39 whereas acombustion flame and combustion gas pass through a space 63 surroundedby the inner shell 61.

The vertical liquid pipe groups 37 are divided into three liquid pipegroups 37A, 37B and 37C: a first group 37A of liquid pipes the closestto the burner 5, a second group 37B of liquid pipes slightly far fromthe burner 5 and a third group 37C farther than the second group 37B ofliquid pipes. Therefore, the third group 37C of liquid pipes arranged ona side opposite to the burner 5 are provided on the side of a combustiongas outlet 43 and fins 45 are provided in each liquid pipe 39 so thatheat can be collected from a combustion gas which is now an exhaust gashaving a slightly lowed temperature.

A diluted absorption solution inlet 47 is provided above the third group37C of liquid pipes and made open to the atmosphere of an upper portion(gas phase portion) of the upper surface portion 41A of the can wall 41.

The diluted absorption solution flowing into the high-temperatureregenerator 4 has passed through the heat exchangers 7 and 8 (FIG. 1)and its temperature has fallen below a boiling start temperature in thehigh-temperature regenerator 4 due to the characteristics of the heatexchangers 7 and 8. This diluted absorption solution having a lowtemperature is caused to flow in from above the third group 37C ofliquid pipes by the pump pressure of the absorption solution pump P andis sprinkled in an open state.

The sprinkled diluted absorption solution falls through the liquid pipes39 of the third group 37C and the side surface portions 41C of the canwall 41. At this point, it collects the heat of the exhaust gas and itstemperature rises. Thereafter, it flows into the lower surface portion41B of the can wall 41 communicating with lower portions of the liquidpipes 39 of the third group 37C. The diluted absorption solution whichhas flowed into the lower surface portion 41B and whose temperature hasincreased to a point near the boiling start temperature flows into lowerportions of the liquid pipes of the second group 37B and the first group37A, is heated and rises together with the rise of air bubbles generatedby boiling in the pipes. Thus, a large circulation flow (shown by arrowsin the figures) is formed in the entire high-temperature regenerator.

Since the temperature of the diluted absorption solution increases to apoint near the boiling start point (saturation temperature) when thediluted absorption solution falls through the liquid pipes of the thirdgroup 37C, it boils immediately in the liquid pipes of the second group37B and the third group 37C and its circulation flow is activated byboiling. Particularly, it can be boiled entirely from the lower portionsof the liquid pipes 39. The circulation flow activated by boilingprevents the retention of the diluted absorption solution and increasestotal heat transfer coefficient. The diluted absorption solution whichis heated uniformly and sufficiently flows out to the outside from anunshown discharge portion.

Heating is carried out uniformly and sufficiently by an increase in heattransfer coefficient due to the activated circulation flow, therebymaking it possible to prevent a local rise in temperature in thevertical liquid pipe groups 37 and the can wall 41. Therefore, it ispossible to prevent a corrosion accident and the crystallization of asolution which are considered to be caused by overheating due to localheating.

(Second Embodiment)

A second embodiment of the present invention is described hereinunderwith reference to FIG. 3A to FIG. 3C. Portions having the same functionsas those described with reference to the above figures are given thesame reference symbols and their descriptions are omitted as far as theunderstanding of the present invention is not prevented (this alsoapplied to a third embodiment of the present invention to be describedlater).

In the first embodiment, the solution inlet 47 is provided above thecenter of the last row of liquid pipes out of a plurality of rows ofliquid pipes of the third group 37C (FIG. 2A). In the second embodiment,as shown in FIGS. 3A to 3C, solution inlets 47 may be provided in upperportions of both right and left sides of a portion on a side opposite tothe burner 5 of the can wall 41. In other words, a pipe constituting thesolution inlet 47 separates into right and left branch pipes 48 by whichthe diluted absorption solution may be sprinkled over upper portions ofthe side surface portions 41C on both right and left sides of the canwall 41.

Since the side surface portions 41C of the can wall 41 have a lowertemperature than the liquid pipes 39 of the third group 37C owing totheir relationship with the combustion gas, they are suitable forforming a downflow of the diluted absorption solution. Therefore,according to this embodiment, a stronger downflow can be obtained andhence, a circulation flow of the diluted absorption solution can beformed more positively.

(Third Embodiment)

A third embodiment of the present invention is described hereinunderwith reference to FIG. 4A to FIG. 4C.

In the above second embodiment, the branch pipes 48 constituting thesolution inlet 47 are open, as shown in FIG. 3A to FIG. 3C, at the lastrow of liquid pipes out of a plurality of liquid pipes of the thirdgroup 37C in the flow direction of the combustion gas and at the sidesurface portions 41C of the can wall 41 in a direction perpendicular tothe flow direction of the combustion gas, that is, a horizontaldirection.

However, as shown in FIG. 4A to FIG. 4C of the third embodiment, thebranch pipe 48 constituting the solution inlet 47 may be bent into a Ushape on a plane (FIG. 4A) and laid along upper portions of the sidesurface portions 41C on both right and left sides of the can wall 41 anda plurality of inlets 49 for sprinkling the diluted absorption solutionmay be distributed in a longitudinal direction of the branch pipe 48.

Since the side surface portions 41C of the can wall 41 generally have alower temperature than the liquid pipes 39 of the vertical liquid pipegroups 37 owing to their relationship with the combustion gas, they aresuitable for forming a downflow of the diluted absorption solution.Therefore, according to this embodiment, a stronger downflow can beobtained by the side surface portions 41C of the can wall 41 and acirculation flow of the diluted absorption solution can be formed morepositively together with an upflow naturally obtained in the verticalliquid pipe groups 37 having a higher temperature.

While the solution inlets 47 in the high-temperature regenerator 4 areprovided in upper portions of the side surface portions 41C on bothright and left sides of the can wall 41 in the second and thirdembodiments, a solution inlet may be provided in an upper portion of theside surface portion 41C on either side.

(Fourth Embodiment)

A fourth embodiment of the present invention is described hereinunderwith reference to FIG. 5 and FIG. 6A to FIG. 6D.

In the above first to third embodiments, the solution inlet(s) 47is(are) provided on a side opposite to the burner 5. In the fourthembodiment as shown in FIG. 5 and FIG. 6A to FIG. 6D, the solutioninlets 47 may be provided below the first group 37A of liquid pipesarranged on the side of the burner 5.

For instance, the diluted absorption solution is received by a dilutedabsorption solution inflow box 51 provided below the first group 37A ofliquid pipes and flows into lower portions of the liquid pipes 39 of thefirst group 37A from the solution inlets 47 formed in the dilutedabsorption solution inflow box 51. Thereafter, the plurality of solutioninlets 47 formed in the diluted absorption solution inflow box 51 areformed of nozzles as shown in FIG. 6(D), each of which extends throughthe outer shell 60 making the lower surface portion 41B of the can wall41 a double structure and projects into the inside of the doublestructure of the lower surface portion 41B toward a lower portion ofeach liquid pipe 39. The projecting nozzles correspond to the number ofliquid pipes 39 of the first group 37A. The inner diameter of each ofthe nozzles is smaller than the inner diameter of each of the liquidpipes 39 of the first group 37A.

Therefore, the diluted absorption solution supplied by pump pressure issprinkled from the nozzles and flows vigorously only into the lowerportions of the liquid pipes 39 of the first group 37A. Thereby, astrong upflow which is combined with an upflow obtained naturally byheating in the first group 37A of liquid pipes is obtained. Acirculation flow of the diluted absorption solution can be formed morepositively by this upflow and downflows generated in the side surfaceportions 41C of the can wall 41.

The diluted absorption solution which flows in as a strong upflow haspassed through the heat exchangers 7 and 8 (FIG. 5) and its temperaturehas fallen below the boiling start temperature in the high-temperatureregenerator 4 due to the characteristics of the heat exchangers 7 and 8.The temperature of a combustion flame from the burner 5 can be reducedpositively and the discharge of NOx contained in the combustion gas canbe reduced by this diluted absorption solution having a low temperature.

(Fifth Embodiment)

A fifth embodiment of the present invention is described hereinunderwith reference to FIG. 7 and FIG. 8A to FIG. 8C.

In FIG. 1 and FIG. 2A to FIG. 2C of the first embodiment, the solutioninlet 47 is provided on a side opposite to the burner 5. In FIG. 5 andFIG. 6A to FIG. 6C of the fourth embodiment, the solution inlets 47 areprovided below the first group 37A of liquid pipes arranged on the sideof the burner 5. However, as shown in FIG. 7 and FIG. 8A to FIG. 8C ofthe fifth embodiment, the two different types of solution inlets 47 canbe provided.

In FIG. 8A to FIG. 8C, the solution inlet 47 of the high-temperatureregenerator 4 of the first embodiment is indicated as a solution inlet47-1 and the solution inlets 47 of the high-temperature regenerator 4 ofthe fourth embodiment as solution inlets 47-2. In FIG. 7, the dilutedabsorption solution pipe 6 extending from the absorber 3 to thehigh-temperature regenerator 4 separates into branch pipes 6-1 and 6-2which communicate with the solution inlets 47-1 and 47-2, respectively.

Thereby, this embodiment can obtain both effects of the first embodimentand the fourth embodiment.

In FIG. 8A to FIG. 8C, like the first embodiment, the solution inlet47-1 is provided above the third group 37C of liquid pipes arranged on aside opposite to the burner 5. As a modification, like the secondembodiment, the solution inlets 47-1 may be provided in upper portionsof both right and left side surface portions 41C or an upper portion ofeither one of the side surface portions 41C of the can wall 41 on a sideopposite to the burner. Like the third embodiment, the solution inlets47-1 may be distributed in a longitudinal direction of the upperportions of both right and left side surface portions 41C or an upperportion of either one of the side surface portions 41C of the can wall41.

A flow control valve may be provided in either one of the branch pipes6-1 and 6-2 to adjust the ratio of the diluted absorption solution to besupplied to the high-temperature regenerator 4 through the solutioninlets 47-1 and 47-2 (this applies to the following embodiments to bedescribed later).

(Sixth Embodiment)

A sixth embodiment of the present invention is described hereinunderwith reference to FIG. 5 and FIG. 9A to FIG. 9C.

In the above fourth embodiment, the diluted absorption solution flowinginto the lower portions of the liquid pipes of the first group 37A flowsinto upper portions of the liquid pipes of the second group 37B and thethird group 37C communicating with each other in a closed state fromupper portions of the liquid pipes of the first group 37A (FIG. 6A toFIG. 6C). However, in the sixth embodiment, the diluted absorptionsolution is sprinkled and caused to flow from upper portions of theliquid pipes of the first group 37A into upper portions of the liquidpipes of the third group 37C in an open state.

In other words, the can wall 41 around the first group 37A of liquidpipes is separated from the can wall 41 around the other second group37B and third group 37C by a partition wall 53. The upper surfaceportion 41A of the can wall 41 around the first group 37A communicateswith a sprinkling pipe 55 extending through the partition wall 53 andthe sprinkling pipe 55 extends in the upper surface portion 41A of thecan wall 41 surrounding the second group 37B and third group 37C ofliquid pipes and is open to upper portions of the liquid pipes of thethird group 37C. Thereby, the diluted absorption solution is sprinkledand caused to flow into the upper portions of the liquid pipes of thethird group 37C in an open state.

According to this sixth embodiment, the total amount of the dilutedabsorption solution which has passed the high-temperature heat exchanger8 flows into lower portions of liquid pipes of the first group 37Athrough the diluted absorption solution inflow box 51 as shown in FIG.5.

According to this sixth embodiment, in addition to the effects of thefourth embodiment, the following effects can be obtained. That is, thefirst group 37A of liquid pipes functions as a preheater and sprinklesand flows the diluted absorption solution flowing in by pump pressureinto upper portions of the liquid pipes of the third group 37C in anopen state, thereby making it possible to promote the generation ofrefrigerant vapor. By the function of the partition wall 53, it ispossible to cause the diluted absorption solution having a lowtemperature to stay in the proximity of the first group 37A of liquidpipes sufficiently, lower the temperature of a combustion flame moresufficiently, and further reduce the discharge of NOx.

(Seventh Embodiment)

A seventh embodiment of the present invention is described hereinunderwith reference to FIG. 7 and FIG. 10A to FIG. 10.

In the above sixth embodiment, the total amount of the dilutedabsorption solution which has passed the high-temperature heat exchanger8 flows into lower portions of the liquid pipes of the first group 37A.However, in this seventh embodiment, part of the diluted absorptionsolution flows into lower portions of the liquid pipes of the firstgroup 37A and the other part is sprinkled over upper portions of theliquid pipes of the third group 37C in an open state.

In other words, in FIG. 7, the diluted absorption solution pipe 6extending from the absorber 3 to the high-temperature regenerator 4separates into branch pipes 6-1 and 6-2, whereby the diluted absorptionsolution from the high-temperature heat exchanger 8 is divided, part ofthe divided diluted absorption solution is caused to flow in from thesolution inlet 47-1 and the other part from the solution inlets 47-2.The diluted absorption solution which flows in from the solution inlets47-2 and flows out from upper portions of the liquid pipes of the firstgroup 37A is sprinkled over upper portions of the liquid pipes of thethird group 37C together with the other part of the diluted absorptionsolution which flows in from the solution inlet 47-1.

Thereby, the amount of the diluted absorption solution flowing in fromthe solution inlets 47-2 can be adjusted, thereby making it possible tocontrol the degree of a reduction in the temperature of a combustionflame.

According to this embodiment, the diluted absorption solution issprinkled in an open state over upper portions of the liquid pipes ofthe third group 37C, that is, upper portions of the liquid pipes 39arranged on a side opposite to the burner, out of the vertical liquidpipe groups 37. As a modification, like the second embodiment, thediluted absorption solution may be sprinkled over the upper portions ofboth right and left side surface portions 41C or an upper portion ofeither one of the side surface portions 41C on a side opposite to theburner of the can wall 41. Like the third embodiment, it may besprinkled over locations distributed in a longitudinal direction ofupper portions of both right and left side surface portions 41C or anupper portion of either one of the side surface portions 41C of the canwall 41.

The high-temperature regenerator 4 (FIG. 10A to FIG. 10C) of the seventhembodiment and the high-temperature regenerator 4 (FIG. 8A to FIG. 8C)of the fifth embodiment may be configured such that, as shown in FIG.11, the branch pipes 6-1 and 6-2 are separated from each other after thelow-temperature heat exchanger 7 and before the high-temperature heatexchanger 8 and the branch pipe 6-1 is connected to the solution inlet47-1 and the branch pipe 6-2 to the solution inlets 47-2, respectively.

According to the above connections, the temperature of the dilutedabsorption solution flowing in from the solution inlets 47-2 can befurther lowered, thereby making it possible to further reduce thetemperature of a combustion flame. Therefore, the temperature of thecombustion flame can be lowered more sufficiently and the discharge ofNOx can be further reduced.

(Eighth Embodiment)

An eighth embodiment of the preset invention is described hereinunderwith reference to FIG. 1 and FIG. 12A to FIG. 12C.

The first, second and third groups 37A, 37B and 37C of liquid pipes areseparated from one another by partition walls 54a and 54b provided inthe double can wall 41 and the flow of the diluted absorption solutionis determined by these partition walls.

The diluted absorption solution flowing into the high-temperatureregenerator 4 has passed through the heat exchangers 7 and 8 (FIG. 1)and its temperature has fallen below the boiling start temperature inthe high-temperature regenerator 4 due to the characteristics of theseheat exchangers. The diluted absorption solution having a lowtemperature flows from the solution inlet 47 above the third group 37Cof liquid pipes, making use of the pump pressure of the absorptionsolution pump P but does not flow into the upper surface portion 41A ofthe can wall 41 surrounding the second group 37B and the first group 37Aof liquid pipes by the function of the partition wall 54a and fallsthrough the liquid pipes 39 of the third group 37C and the side surfaceportions 41C of the can wall 41 surrounding the third group 37C ofliquid pipes. At this point, the diluted absorption solution collectsthe heat of an exhaust gas to increase its temperature. Thereafter, thediluted absorption solution is guided into a bypass pipe 38 by thefunction of the partition wall 54a below the liquid pipes 39 of thethird group 37C and flows into lower portions of the liquid pipes of thefirst group 37A. At this point, since the temperature of the dilutedabsorption solution is elevated to a point near the boiling start point,it boils immediately in the liquid pipes of the first group 37A and itsflow is activated by boiling, whereby the heat transfer coefficient isincreased. The diluted absorption solution heated sufficiently by theincreased heat transfer coefficient is further boiled and concentrated.

A high heat transfer coefficient makes it possible to prevent a rise intemperature in the first group 37A of liquid pipes where inconvenienceis liable to occur by a rise in temperature. The diluted absorptionsolution does not flow into lower portions of the liquid pipes of thesecond group 37B by the function of the partition wall 54b but runs upthrough the liquid pipes of the first group 37A. The diluted absorptionsolution which has run up does not flow into the liquid pipes of thethird group 37C by the function of the partition wall 54a but flows intoupper portions of the liquid pipes of the second group 37B, falls,reaches lower portions of the liquid pipes of the second group 37B, andflows out to the outside from an unshown discharge portion.

In this embodiment, the diluted absorption solution collects the heat ofan exhaust gas while it passes through the liquid pipes of the thirdgroup 37C to increase its temperature to a point near the boiling startpoint. Therefore, it starts boiling immediately in the liquid pipes ofthe first group 37A and is heated in the liquid pipes of the first group37A and the second group 37B while it is changed by the temperature oflatent heat.

Thus, the diluted absorption solution is heated in the liquid pipes ofthe first group 37A while it is boiled in this embodiment. In otherwords, boiling is possible in all of the liquid pipes of the first group37A. Then, the flow of the diluted absorption solution is activated byboiling, and heat transfer coefficient is increased by this activatedflow. Therefore, it is possible to prevent local heating in the liquidpipes of the first group 37A, particularly local heating in lowerportions of the liquid pipes of the first group 37A. As a result, acorrosion accident and the crystallization of a solution which areliable to occur in the liquid pipes of the first group 37A can beprevented.

(Ninth Embodiment)

A ninth embodiment of the present invention is described hereinunderwith reference to FIG. 1 and FIG. 13A to FIG. 13C.

This ninth embodiment is configured such that the diluted absorptionsolution is caused to flow into lower portions of the liquid pipes ofthe first group 37A directly without passing through the liquid pipes ofthe third group 37C.

In other words, the pump pressure of the absorption solution pump P isused to cause the diluted absorption solution to flow into the lowerportions of the liquid pipes of the first group 37A (FIG. 1). Thediluted absorption solution supplied by the pump pressure is firstguided into the diluted absorption solution inflow box 51 located belowthe liquid pipes of the first group 37A only.

The diluted absorption solution inflow box 51 communicates with thelower surface portion 41B below the liquid pipes 39 of the first group37A through the solution inlets 47 which are formed smaller in innerdiameter than the liquid pipes 39 of the first group 37A at positionscorresponding to the lower portions of the liquid pipes 39 of the firstgroup 37A.

The diluted absorption solution flows vigorously from the solutioninlets 47 having a small diameter, making use of the pump pressure andis guided only into the lower portions of the liquid pipes of the firstgroup 37A by the function of the partition wall 54b. In other words, thediluted absorption solution does not flow into the side surface portions41C of the can wall 41 surrounding the first group 37A of the liquidpipes and lower portions of the liquid pipes of the second group 37B.

The diluted absorption solution which flows vigorously into lowerportions of the liquid pipes of the first group 37A reaches upperportions of the liquid pipes and falls vigorously through the sidesurface portions 41C of the can wall 41. Since the diluted absorptionsolution is caused to flow vigorously from lower portions of the liquidpipes of the first group 37A, the diluted absorption solutiontherearound, that is, the diluted absorption solution present in theunder surface portion 41B of the can wall 41 communicating with thelower portions of the liquid pipes of the first group 37A is draggedinto the above diluted absorption solution and flows into the liquidpipes of the first group 37A. Further, the heated diluted absorptionsolution flows up in the liquid pipes 39. Owing to these, as shown byarrows in FIG. 13C, the diluted absorption solution forms a large flowas a whole.

Thanks to this flow, the diluted absorption solution is not retained,thereby making it possible to prevent the formation of a portion heatedto an extremely high temperature only in a part of the vertical liquidpipe groups. By preventing such a local rise in temperature in this way,even if the pump for flowing in the diluted absorption solutionmalfunctions, the occurrence of a burn-out can be prevented.

As described above, according to the first aspect of the presentinvention, since the diluted absorption solution is caused to flow intoupper portions of liquid pipes arranged on a side opposite to the burnerand is sprinkled in an open state, the sprinkled diluted absorptionsolution falls through the liquid pipes nearby. The diluted absorptionsolution in the other liquid pipes, that is, the liquid pipes near theburner, is heated and flows up. In this way, a large circulation flow isformed in the entire high-temperature regenerator. Since the sprinkleddiluted absorption solution collects the heat of an exhaust gas while itfalls to increase its temperature, when it flows into the other liquidpipes, it boils immediately and its circulation flow is activated byboiling. Therefore, total heat transfer coefficient can be increased, alocal rise in the temperature of the liquid pipe groups and the can wallcan be avoided, and such inconvenience as a corrosion accident and thecrystallization of a solution caused by this rise in temperature can beprevented. Further, the sprinkled diluted absorption solution generatesrefrigerant vapor, whereby its concentration is promoted.

According to the second aspect of the present invention, since thediluted absorption solution is caused to flow into upper portions ofboth right and left sides or an upper portion of either one of the sidesof a portion on a side opposite to the burner of the double can wall andis sprinkled in an open state, the sprinkled diluted absorption solutionfalls mainly through the side surface portions of the can wall.Thereafter, the diluted absorption solution in the liquid pipes isheated and flows up. Thus, a large circulation flow is formed in theentire high-temperature regenerator. Since the sprinkled dilutedabsorption solution collects the heat of an exhaust gas while it fallsto increase its temperature, it boils immediately when it circulates inthe liquid pipes and its circulation flow is activated by boiling.Therefore, total heat transfer coefficient can be increased and a localrise in the temperatures of the liquid pipes and the can wall can beavoided, and such inconvenience as a corrosion accident and thecrystallization of a solution caused by this rise in temperature can beprevented. The sprinkled diluted absorption solution generatesrefrigerant vapor, whereby its concentration is promoted.

According to the third aspect of the present invention, since thediluted absorption solution is distributed in a longitudinal directionof upper portions of both right and left sides or an upper portion ofeither one of the sides of the double can wall and is sprinkled in anopen state, the sprinkled diluted absorption solution falls through theside surface portions in a longitudinal direction of the can wall. Thediluted absorption solution in the liquid pipes is heated and flows up.Thus, a large circulation flow is formed in the entire high-temperatureregenerator. Since the sprinkled diluted absorption solution collectsthe heat of an exhaust gas while it falls to increase its temperature,it boils immediately while it flows into the liquid pipes and itscirculation flow is activated by boiling. Therefore, total heat transfercoefficient can be increased, a local rise in the temperatures of theliquid pipes and the can wall can be avoided, and such inconvenience asa corrosion accident and the crystallization of a solution caused bythis rise in temperature can be prevented. The sprinkled dilutedabsorption solution generates refrigerant vapor, whereby itsconcentration is promoted.

According to the fourth aspect of the present invention, since thediluted absorption solution is caused to flow into lower portions ofliquid pipes arranged on the side of the burner by pump pressure, astrong upflow which is joined with an upflow obtained naturally byheating in the liquid pipes can be obtained and a circulation flow ofthe diluted absorption solution can be formed more positively by thisupflow and downflows generated in other portions. Therefore, total heattransfer coefficient can be increased, a local rise in the temperaturesof the liquid pipes and the can wall can be avoided, and suchinconvenience as a corrosion accident and the crystallization of asolution caused by this rise in temperature can be prevented. Thediluted absorption solution flowing into the lower portions of theliquid pipes arranged on the side of the burner can lower thetemperature of a combustion flame from the burner positively and reducethe discharge of NOx contained in the combustion gas.

According to the fifth aspect of the present invention, the effects ofthe first, second and third aspects as well as the effect of the fourthaspect of the present invention can be obtained.

According to the sixth aspect of the present invention, the dilutedabsorption solution is caused to flow into lower portions of liquidpipes arranged on the side of the burner by pump pressure, is heated, iscaused to flow out from upper portions of the liquid pipes, andsprinkled over a plurality of liquid pipes arranged in another portionin an open state, the following effect can be obtained in addition tothe effect of the fourth aspect. That is, the generation of refrigerantvapor can be promoted by sprinkling the diluted absorption solution inan open state. The diluted absorption solution having a low temperaturecan be retained in the liquid pipes arranged on the side of the burnersufficiently, the temperature of a combustion flame can be lowered moresufficiently and the discharge of NOx can be further reduced.

According to the seventh aspect of the present invention, part of thediluted absorption solution which has exchanged heat with thelow-temperature heat exchanger or both the low-temperature heatexchanger and the high-temperature heat exchanger is caused to flow infrom the first solution inlets by pump pressure, the following effectcan be obtained in addition to the effect of the sixth aspect of thepresent invention. That is, the amount of the diluted absorptionsolution to be supplied to liquid pipes on the side of the burner can beadjusted, thereby making it possible to control the degree of areduction in the temperature of a combustion flame.

The diluted absorption solution which has flown in from the firstsolution inlets and has flown out from upper portions of liquid pipesarranged on the side of the burner is caused to flow into upper portionsof liquid pipes arranged on a side opposite to the burner, or upperportions of both right and left sides or an upper portion of either oneof the sides of a portion on a side opposite to the burner of the doublecan wall, or in locations distributed in a longitudinal direction ofupper portions of both right and left sides or an upper portion ofeither one of the sides of the can wall together with the other part ofthe branching diluted absorption solution and is sprinkled in an openstate. Thereby, the effects of the first, second and third aspects ofthe present invention described above are obtained.

According to the eighth aspect of the present invention, since thediluted absorption solution is caused to pass through the liquid pipesof the third group to collect the heat of an exhaust gas and reach theboiling start temperature, or is caused to pass through the liquid pipesof the first group and the second group after its temperatureapproximates to the boiling start temperature sufficiently, the flow ofthe diluted absorption solution can be activated by boiling. Thereby,heat transfer coefficient can be increased, a local rise in thetemperatures of the liquid pipe groups and the can wall can be avoided,and such inconvenience as a corrosion accident and the crystallizationof a solution caused by this rise in temperature can be prevented.

According to the ninth to twelfth aspects of the present invention, whenthe diluted absorption solution is caused to flow from lower portions ofthe liquid pipes of the first group, an upflow is formed positively inthe first group of liquid pipes by regulating an inflow into the sidesurface portions of the double can wall and introducing the dilutedabsorption solution only into lower portions of the liquid pipes of thefirst group, whereby the flow of the diluted absorption solution isactivated as a whole, thereby making it possible to prevent a local risein temperature.

What is claimed is:
 1. A high-temperature regenerator which has verticalliquid pipe groups in the proximity of which a combustion flame andcombustion gas from a burner pass and a double can wall whichcommunicates with upper and lower portions of liquid pipes forming thevertical liquid pipe groups and is arranged at a position of a furnacewall and which heats and concentrates a diluted absorption solutionpassing through the vertical liquid pipe groups and the double can wall,wherein the high-temperature regenerator comprises:dividing means fordividing the liquid pipes into liquid pipes arranged on the side thereofso that they do not communicate with each other; solution inlets forcausing the diluted absorption solution to flow into lower portions ofliquid pipes on the side of the burner by means of pump pressure; andsprinkling means for sprinkling the diluted absorption solution flowingout from upper portions of the liquid pipes on the side of the burnerover upper portions of the liquid pipes at a downstream side in an openstate.
 2. The high-temperature regenerator according to claim 1, whereinthe solution inlets for causing the diluted absorption solution to flowin by means of pump pressure have an introduction structure formed byopenings for passing the diluted absorption solution and guide means forregulating an inflow of the diluted absorption solution into sideportions of the double can wall and guiding it mainly into lowerportions of the liquid pipes.